1. Field of the Invention
The present invention relates to a food processor for preparing foodstuffs.
2. Prior Art
Such appliances are known, and they enable various attachments such as chopping blades, grating and shredding disks, liquidizers, etc. to be mounted inside a bowl, the attachments being rotated inside the bowl by an electric motor disposed in a base and having its shaft projecting into the bowl.
In certain household food processors, such as the one described in U.S. Pat. No. 3,892,365 (Verdun), the motor is housed in a base, with the bowl being mounted on the base and therefore above the motor. The bottom of the bowl surrounds a base plate provided with lugs which are inserted into grooves when the bowl is mounted on the base, so that the bowl is held stationary in a determined position on the base.
It is essential for consumer appliances to be provided with safety means designed to prevent injuries to users. In the above-mentioned patent, such safety means are obtained by a safety rod which enables the appliance to operate, i.e. which enables the motor to be started, only when the bowl is properly attached to the base, and when the lid closing the bowl is in the closed position. In this way, it is impossible for there to be any contact between the hands of the user and an attachment that is rotating. In that known device, the push-rod, which is vertically movable under the action of a spring and of a cam provided on the lid, extends along a channel formed along a generator line of the cylindrical bowl, the spring being mounted in the bottom portion of said channel.
The bowl stands on its bottom on a base plate projecting from the top surface of the base. The bowl has a skirt which surrounds the base plate. Said skirt is provided with grooves (in practice, there are three such grooves) in which lugs are inserted, thereby constituting a bayonet locking system.
That locking system performs the following functions:
it centers the bowl relative to the base; PA1 it locks the bowl in position vertically; and PA1 it prevents the bowl from rotating. PA1 centering is performed by mutual cylindrical engagement between the chimney in the bowl and the sleeve surrounding the drive means; PA1 the bowl is prevented from being pulled off vertically by the stud-lug assembly; the bowl can thus rotate about the sleeve of the drive shaft; and PA1 the bowl is prevented from being rotated by an eccentric abutment; the eccentric abutment enables the bowl to be locked angularly in a determined position that corresponds to the position of the push-rod when it is in alignment with a hole provided in the base so as to enable said push-rod to act on a safety switch.
Naturally, however, only a bowl that has dimensions corresponding to those of the base can be mounted thereon. Depending on the type of preparation, it is convenient to be able to use bowls having various capacities. Moreover, that locking system requires the presence of a base plate, and this may be a drawback.
It has already been proposed in Document FR-A-2 498 438 to use the sleeve surrounding the drive shaft to fasten the bowl, said sleeve being provided with notches which receive lugs that are formed in the central chimney of the bowl. Unfortunately, any forces that are exerted at the periphery of the bowl are multiplied in the central portion thereof by leverage, and this means that the fastening system is unsecure.